Wikipedia:Reference desk/Archives/Science/2008 October 5

= October 5 =

How to Get Gray Hair
I understand there is a multitude of products in current circulation designed to rid people of gray hair, which is a process that I am not in the market for. I actually want the exact opposite. My hair is a dark brown/black, and I want it to have a nice Andy Warhol/Randy Newman gray tone. What should I look into regarding this? Is it even possible? Thank you folks. Kenjibeast (talk) 02:36, 5 October 2008 (UTC)
 * Hydrogen peroxide and ammonia will strip the color out of your hair, but it will leave it a whitish blonde, not gray. :( --Russoc4 (talk) 03:11, 5 October 2008 (UTC)


 * Keep in mind that Warhol wore a wig. Dying your hair to that level of white is possible but it's not easy and it's not very good for the hair. I don't know how you'd get it gray rather than white, though. --98.217.8.46 (talk) 04:01, 5 October 2008 (UTC)


 * Get a stressful job or go to graduate school in some crazy competitive field like biochem. It's guaranteed to work though it does take some time. Comes with free wrinkles too ;) Sjschen (talk) 04:20, 5 October 2008 (UTC)


 * Just wait: time has a tendency to take care of such things. ៛ Bielle (talk) 04:31, 5 October 2008 (UTC)
 * This evidence is anecdotal, but ever notice how all the US presidents look so old after just 4-8 years? Stress does seem to assist with the graying. This does pose the question, does stress induced graying recover with the relief of stress? Sjschen (talk) 04:49, 5 October 2008 (UTC)
 * That's not just anecdotal, plenty of others have noticed it too. I've read articles on it, but I can't find any now. It looks like ABC had a slideshow on it, but has since taken it offline.  Plasticup  T / C  15:45, 5 October 2008 (UTC)
 * Playing devil's advocate for a moment, I think it's worth noting that most new Presidents are into what might be charitably described as 'late middle age' by the time that they take office. According to List of United States Presidents by age, the average age of a new President is 55 years.  Add four or eight years on to that, and and they're eligible for senior's discounts at a lot of retailers.  In other words, they look so old because they've gotten so old.  Compare photographs of the average non-President at ages 55 and 63, and you might notice that they've aged, too. TenOfAllTrades(talk) 19:42, 5 October 2008 (UTC)
 * I considered that, yes. I think it would be interesting to test it.  Plasticup  T / C  19:53, 5 October 2008 (UTC)


 * Even the young presidents (Clinton, Kennedy) look much older after a few years in office. --Carnildo (talk) 22:24, 5 October 2008 (UTC)
 * In that case, how does stress induce greying? How does melanine production get turned off in such a manner? Sjschen (talk) 21:04, 5 October 2008 (UTC)
 * Exactly. ---J.S (T/C/WRE) 01:31, 6 October 2008 (UTC)

This sounds like a problem that actors would be faced with, as they may have to play the same character at different ages. I suggest trying a supplier of theatrical cosmetics. --Anonymous, 04:44 UTC, October 5, 2008.


 * Having teenage children is a tried and true method for getting gray hair. You also might ask to borrow some teenagers if the time constraints of raising your own are a problem. Edison (talk) 20:22, 5 October 2008 (UTC)


 * Scientific American took up the question of stress and gray hair. There are some other interesting notes there, too.  Keep in mind the hair isn't just one shade of gray -- as the melanocyte cells fail, there's less and less pigment; when there's none, the hair appears white.  Also, blondes seem to turn gray later, because the white doesn't stand out as much against the blonde.  --- OtherDave (talk) 00:59, 7 October 2008 (UTC)

Alright, apart from getting a wig, looking for theatrical cosmetics, and applications of constant stress, are there any permanent methods to grey my hair out? By permanent I don't mean forever, I just mean it won't wash out, dig? Thanks folks, you've been a great help so far. Kenjibeast (talk) 05:59, 7 October 2008 (UTC)


 * A suggestion: if getting a new colour is about applying a colour, and greying is a process of colour loss, it's unlikely there's a colour to give you grey on top of your dark hair. But – you could have someone make it blond to white and add a toner (example). There are also British made water colour hair colours that go into a paintbox range that show up best on lightened hair, but can't find them through google. PS what colour was Warhol's original hair? Julia Rossi (talk) 06:57, 11 October 2008 (UTC)

Nomex
How fire/heat resistant is Nomex? I can find all sorts of words like "very" and "extremely", but no hard numbers. --67.185.172.158 (talk) 09:12, 5 October 2008 (UTC)
 * Nomex is meant to save you from flash injury, it's not really made for running into fires. As such, you won't necessarily find "hard" numbers. Suffice to say, if a pool of flammable liquid ignites 20 feet away, you're better off wearing Nomex. The ejected flammable liquid won't hit your skin and the flames will bounce. If you end up lying in a pool of burning hydrocarbons, you will still have to get up and run. Franamax (talk) 09:39, 5 October 2008 (UTC)
 * "The rate of material decomposition and charring rate is high only after the temperature greatly exceeds 350°С; however, the material does not melt." Also a bunch of other figures not related to using it for protection (e.g. [The unique combination of electrical and mechanical strength, heat resistance (temperature rating of 220°С]). Perhaps you can find some graphs showing decomposition and stuff, but I don't really see how you can get any 'harder' then that. I presume precisely what it does will depend on the temperature and time period of exposure and whether it's a naked flame. As Franamax says I think the primary point of Nomex is that it stops flames from hitting your skin and it doesn't itself catch fire in most situations you'd expect to encounter. It's not some sort of extrme insulator so you've still going to get burnt if you stay in a fire/hot temperature for too long Nil Einne (talk) 10:24, 5 October 2008 (UTC)
 * I smell an experiment!  Plasticup  T / C  15:42, 5 October 2008 (UTC)
 * We'd better hope that the experiment doesn't lead to our smelling a burnt body. --M1ss1ontomars2k4 (talk) 21:17, 5 October 2008 (UTC)
 * Fire-suite manufactures do internal testing and are loathe to share their results. It's the same in any very specialized industry... the research is just too expensive to share with their competitors. ---J.S (T/C/WRE) 01:35, 6 October 2008 (UTC)
 * Nomex coveralls are also horribly uncomfortable, since they retain your sweat. I always used ProbanTM, which was treated cotton, and I got away with it 'cause I was the manufacturer's rep and could explain that I threw them away after ten washings. In any of my safety-trainings (one per chemical plant) I was told the rule that no sleeves could be rolled up, and that Nomex was the just-in-case for "uncontrolled ignitions" and that all normal evacuation procedures must be followed. Ironically, the protection of the coveralls would mean that only your hands and face would be hideously burnt, but you'd still be alive. I've since eased out of that field of work... Franamax (talk) 23:01, 6 October 2008 (UTC)
 * Err...franamax, as a firefighter, allow me to advise you to qualify your first statement. Nomex hoods are standard issue for firefighters in the united states and therefore are literally made for running into fires. Granted, the protection the hood gives is limited and the first area that usually gets burned (the ears) is under the hood's jurisdiction. NFPA standard 1971 probably has something to say about them if you can find a copy. --Shaggorama (talk) 07:27, 7 October 2008 (UTC)

Hyperthyroidism and the risks of general asesthesia/surgery
I was recently scheduled for a hysterectomy and the Surgeon cancelled the surgery because of the TSH result from my pre-op blood test. If the T3 & T4 results are in the reference range is there a risk of going under general anesthesia? If so, are they and what are the statistics? —Preceding unsigned comment added by Istaffordcomcastnet (talk • contribs) 17:04, 5 October 2008 (UTC)


 * Your surgeon, your consultant and other doctors involved in your treatment know your medical history and your test results and are obviously a much more reliable source of information than random strangers on the internet. So ... wouldn't it be better to put your questions to them ? Gandalf61 (talk) 17:26, 5 October 2008 (UTC)
 * There does appear to be an interaction between thyroid horormones and some specific anesthetics and/or major surgery. Googling for t3 t4 tsh anesthesia finds some refs. Even though this isn't (to my reading) a request for medical advice, your doctor could at least tell you the specific guidelines he's following. That would be a great starting point to finding out the basis for those guidelines and the risks that specific deviations would entail. DMacks (talk) 17:31, 5 October 2008 (UTC)

Reasons people mumble - hearing loss, etc.
I'm curious as to the physical reasons people mumble. Specifically, I heard someone say recently that some older people start talking lower because of hearing loss. That sounded strange, because I would think, instinctively, one would speak louder with a hearing loss. I supose the issue could be the "internal volume control," so to speak, where the person just *thinks* they're speaking normally because they're used to not hearing much, anyway. It just seems so counter-intuitive.; it seems that once you get that volume down when you're a child, it stays, unless you think you have to speak louder.

Also, considering the person mentioned older people, I wonder if mumbling could be due to a heart problem, with not enough oxygen coming to the person. Although, I always though those weak voices of dying people in movies and TV were just dramatized; sure, my grandparents' voices sounded a little weaker toward the end, but not *that* weak. Thanks.Somebody or his brother (talk) 19:33, 5 October 2008 (UTC)


 * In my experience, some muttering is passive aggression. Mumble first, then when someone asks for clarification shout "I SAID...." Other mumbling may reflect shyness or a defense mechanism for fear of being attacked for saying something. Also consider that when it seems like other people are mumbling, it might actually reflect a hearing loss on the part of the listener. Edison (talk) 20:51, 5 October 2008 (UTC)


 * Much of our speech habits is controlled/re-enforced by hearing our own voice or the voice of others. If we lose our hearing we lose that reference and the habits can slip. Ever notice how weird it is to talk with really good sound protection on?
 * Speculation... If an older person is losing their hearing then it's possible they are told a few times too many that they are talking loud... and then they over-compensate in response. ---J.S  (T/C/WRE) 01:29, 6 October 2008 (UTC)


 * A rather simplistic explanation: Humans are inherently designed to put forth the least amount of energy required to complete a given task. If that task is communicating a message, there is not point in speaking in a loud, clear voice when a soft mumble will likely work just fine.  I ride the bus most days.  I hear conversations that sound like, "Isa you gur edda sto."  "Mudu?"  "Yaw."  "Aw, shu gedda da mun etta."  It may sound like nonsense, but it is the minimum effort required for the two to converse.  Sometimes it fails.  I was one of my favorite Chinese food restaurants and the lady in front of me ordered "frump fry fie".  The guy at the register didn't understand.  She asked again for "frump fry fie".  He didn't understand.  After going back and forth a large number of times, a cop behind me asked her if she wanted "shrimp fried rice."  She replied "Fu!" --  k a i n a w &trade; 03:34, 6 October 2008 (UTC)


 * I agree with these answers. In addition, though, think about a feedback loop.  Will the person get positively or negatively reinforced when they begin to dabble in mumbling behavior.  The answer is positive reinforcement, so they will keep winding down the slippery slope.  Plus, you gave stated information that it is about older people.  Society has norms for providing people these unfortunate feedbacks.  Its just an interesting theory, not quite yet a paradox.  It was good though, I liked reading and answering your question. Thanks Sentriclecub (talk) 18:39, 6 October 2008 (UTC)


 * Loss of hearing acuity would sever the feedback link between spoken volume and perceived volume. Also, the volume of your own speaking is largely transmitted through your own skull, so problems at the eardrum mechanism would cause other people's voices to decrease in perceived volume more than your own. It is only the younger cellphone generation who have decided that the solution to poor audio is to SPEAK LOUDER into their own phone. (Incidentally people, you don't have to face outwards on your balcony to get better reception, although it does let everyone know how cool you are. And ain't it strange how all the phones work so well indoors in wintertime, but in summer you suddenly need to give me all the details of your life?) If you can't accurately assess your own relative vocal loudness, it's hard to say whether your own loudness would increase or decrease.
 * That said, I am well-known in various workplaces as "talks to himself" - so to some extent, mumbling is also a vocalized internal conversation. Franamax (talk) 22:37, 6 October 2008 (UTC)
 * I'm the same, Franamax. One of my kids once mentioned in passing how I was talking to myself when I was typing something on my computer.  I said I wasn't aware of it, but if it was true, I must have had something on my mind and it would have been a one-off experience.  I was humbled when he said "Dad, you do it all the time".  Others have since commented on this.  Maybe I'm the Glenn Gould of Wikipedia.  My experience of increasing deafness is that I'm more and more often asked to speak up.  Apparently, to my interlocutors I'm mumbling, but to me I'm speaking at what I think is a normal volume.  What people hear in their own heads when they're speaking is not the same as others hear them.  I'm reminded of this whenever I'm watching TV and munching on a snack.  Whenever I take a bite, I momentarily lose what I'm listening to, and I've learned to do most of my munching during the ad breaks.  --  JackofOz (talk) 23:45, 6 October 2008 (UTC)
 * Well luckily I'm showing no signs whatsoever of aging. There is an increasing trend to smaller font sizes and lower light levels in general, but I'm sure that will change back in time. I too have noticed the new more loudly-crunching snacks that prevent one from hearing the program. This will all doubtless be fixed when the US Democrats come to power. Or was it the Republicans? I'll consider this when I've finished my nap. :) Franamax (talk) 01:09, 7 October 2008 (UTC)


 * "When in doubt, mumble" -- James H. Boren. I know I do that a lot. — DanielLC 23:50, 6 October 2008 (UTC)


 * On a related "what you hear in your head and what others hear is not the same" topic... I very much like to sing when I program. In my head, I hear a voice somewhat in tune with what is coming out of my speakers.  To everyone else, my voice is monotone, nasal, and very annoying.  Hence, I do most of my programming at home, at night, after the family is asleep. --  k a i n a w &trade; 01:21, 7 October 2008 (UTC)
 * You should probably get a small headset-microphone and plug that into your sound-card so you can mix a little of your voice into whatever it is you are singing along to so you can hear yourself as others do. SteveBaker (talk) 11:35, 7 October 2008 (UTC)

Blindness and visual artefacts
Do people who are blind from birth 'see' visual phenomenons, artefacts or hallucinations, perhaps due to the lack of stimulation of the visual cortex? Has anyone got links or refs on that subject. Thank you. 190.244.186.234 (talk) 21:38, 5 October 2008 (UTC)
 * Ah, I already found this: Charles_Bonnet_syndrome. 190.244.186.234 (talk) 21:43, 5 October 2008 (UTC)
 * That article doesn't mention persons who are blind from birth. That syndrome seems to afflict persons who lose their sight later in life.  Plasticup  T / C  04:10, 6 October 2008 (UTC)


 * Almost the exact same question was asked about a month ago and given (in my opinion) thorough treatment. Check out the response here. --Shaggorama (talk) 06:13, 7 October 2008 (UTC)
 * Hurray! Fanx. OP. 190.220.104.35 (talk) 15:38, 7 October 2008 (UTC)

extrusion of rock
What do the extrusion of rock form? Thanks, from my son - for his Science homework. —Preceding unsigned comment added by 76.69.48.237 (talk) 22:12, 5 October 2008 (UTC)


 * All kinds of neat stuff. Extrusive article is a good place to start. -- Finlay McWalter | Talk 22:14, 5 October 2008 (UTC)